That means crossing the Cook Strait, where fierce winds and currents are created as the Pacific Ocean and the Tasman Sea squeeze themselves into the narrow gap between the islands.

The conditions are a big change from international racing for the crew, most of whom have rowed at a top level – German Olympian Tina Manker, World Rowing under-23 medallist for New Zealand Johanna Kearney, junior, under-23 and senior representative for Great Britain Rachel Gamble-Flint and New Zealand rower Eleanor Morris.

Manker, the stroke, says they did lots of endurance cross training and some long open water rows but nothing could really prepare them when they set off in darkness from the North Island for what was to be a 94 kilometre, 11 hour row.

“There was ten seconds between the one-metre swells and on top of that there was a lot of chop,” says Manker.

But when they left the shadow of the land and hit open water, it really ramped up and the self-bailing coastal boat provided by Laszlo came into its own.

“For four hours there was a constant swell and wind from the stroke side,” she says. “A few of the waves would hit you at head level and you’d get completely drenched.”

The rough conditions put an end to their plans to stop for a brief snack every 20 minutes or so.

Instead, each rower took turns to stop for a just few seconds to put some fuel in before quickly keeping pace.

The hardest part came when they had to detour ten kilometres off course to avoid a huge current.

In stroke seat, Manker says it was tough to steer as they turned away from land and she could only see open water. As they arrived in South Island waters, conditions improved.

“We got into shelter and had a brief break but we were drifting out again – and nobody wanted that,” says Manker.

One of the biggest challenges in the four and a half hours in the Cook Strait had been the lack of food so it was a huge morale boost to be able to eat again.

They knew the final 25 kilometres towards the town of Picton well and, because it’s through a sound, they could see the land and track their progress.

“I do really like Picton,” says Tina, "but I have never been so happy to see it.”

The challenge was to raise money for their charity, Through the Blue, set up to improve early intervention for depression and anxiety in high school students. Their aim is to educate teachers about mental health issues so they can in turn help their students.

Manker says the rowing challenge reflects their cause, because although they had to go through a challenge as individuals, they also needed to seek help from experts – ocean rowers, ferry captains, boat builders and many more.

The crew wants to thank the many people who helped them with their challenge and who have donated to the cause.